Breath-enhanced ultrasonic nebulizer and dedicated unit dose ampoule

ABSTRACT

A medicament delivery system comprises a nebulizer device, an open-faced mist chamber-defining element having a tubular input/output port, a tubular inhalation port connecting to the output port of the mist chamber-defining element, and a sealed unit dose ampoule adapted to fit within the mist chamber-defining element. The nebulizer device includes an ultrasonic transducer responsive to applied electrical energy to generate ultrasonic energy, an ultrasonic transmission horn between an input energy surface at an input end and an energy delivery surface at an output end. The sealed unit dose ampoule can be placed directly into the nebulizer device and acts as both the dose cup and baffle, so that the chance of spillage of drug and the number of components to be cleaned are minimized.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage entry under 35 U.S.C. § 371 ofinternational Application PCT/US02/27712, filed Aug. 30, 2002, whichclaims the benefit under § 119e of the filing dates of U.S. ProvisionalApplication 60/318,737 and 60/318,698, both of which were filed on Sep.12, 2001.

FIELD OF THE INVENTION

The invention relates to an apparatus and method for administeringmedicament for inhalation by a patient. More particularly, the presentinvention relates to a nebulizer having a unit dose ampoule and a valvearrangement for use in a nebulizer medicament delivery system.

BACKGROUND OF THE INVENTION

Nebulizers are well known for dispensing medicament to the lungs of apatient for treating asthma, for example. A typical prior art nebulizerassembly for such therapeutic purposes includes a nebulizer whichcontains an electrically driven ultrasonic energy source and a dose cupacoustically coupled to receive ultrasonic energy from the source. Adomed element is removably disposed over the dose cup, establishing asubstantially closed mist chamber-defining element therein. Aninhalation port extends from the domed element, permitting a user toinhale the contents of the mist chamber-defining element. Theconventional practice of nebulizing an aqueous solution in ultrasonic(or jet) nebulizers, involves a first step of removing the domed element(permitting user access to the dose cup), followed by breaking anampoule or vial containing the medicament, and introducing the contentsinto a dose cup or chamber. The domed element is then replaced, and theultrasonic energy source is activated, whereby the ultrasonic energy istransmitted to the dose cup, where it nebulizes the medicament. A usermay then inhale via the inhalation port, as desired.

The method of introducing the medicament to the dose cup involvesprolonged handling of the medicament by the patient and therefore maylead to hygiene issues and volume loss due to spillage or incompleteemptying of the ampoule. A further issue is the number of componentswhich require cleaning following nebulization—dose cup, domed element,inhalation ports of the inhalation port, for example.

It is an object of this invention to provide an improved nebulizerapparatus and method which minimizes spillage of drug and the number ofcomponents to be cleaned.

Another object is to provide an improved nebulizer. Most conventionalnebulizers allow free flow of air through a dose chamber duringnebulization, which results in the exhalation of the patient forcingnebulized mist back into the dose chamber and device during exhalation.As a consequence, a large proportion of the dose condenses on the insideof the device and is therefore not delivered to the lung. It is anotherobject of this invention to provide more efficient air control duringinhalation and particularly exhalation, to significantly improvenebulizer performance.

SUMMARY OF THE INVENTION

The present invention provides a medicament delivery system. Themedicament delivery system comprises a nebulizer, an open-faced mistchamber-defining element, coupling means for selectively coupling thecoupling end of the mist chamber-defining element to the energy deliveryend of the housing, a tubular inhalation port extending between a userend and a device end, and a bidirectional valve assembly.

In a preferred form of the invention, the nebulizer includes a housingextending along a housing axis from a base end to an energy deliveryend. The housing includes an ultrasonic transducer responsive to appliedelectrical energy to generate ultrasonic energy at an output surface,and an ultrasonic transmission horn extending along the housing axisbetween an input energy surface and an output end. The input energysurface is acoustically coupled to the output surface of the transducer.The horn is adapted to transmit ultrasonic energy applied at the inputenergy surface along the housing axis to the energy delivery surface.

The open-faced mist chamber-defining element (which includestransparent, translucent and opaque elements) extends along a chamberaxis from an open-faced coupling end. The mist chamber-defining elementincludes a tubular input/output port extending along a port axis, withthe port axis being angularly offset from the chamber axis e.g., by anangle in the range of 35–55 degrees, such as 45 degrees. Thechamber-defining element is selectively couplable to the energy deliveryend of the housing so that the interior volume of the mist chamber isopposite the energy delivery surface of the horn and the chamber axis issubstantially parallel to the housing axis. Preferably, thechamber-defining element is dome-shaped, so that when its open face iscoupled to the housing, it defines the substantially closed mistchamber.

The bidirectional valve assembly has a first port coupled to the deviceend of the inhalation port, a second port coupled to the port of themist chamber-defining element and a third port coupled to (which, insome embodiments, may be integral with) points exterior to thebidirectional valve assembly. The valve assembly defines aunidirectional airflow path only from the interior volume of the mistchamber to the user end of the inhalation port when the pneumaticpressure in the inhalation port is lower than the pneumatic pressure inthe interior volume of the mist chamber. The valve assembly also definesa unidirectional airflow path only from the user end of the inhalationport to the exterior points when the pneumatic pressure in theinhalation port is greater than the pneumatic pressure in the interiorvolume of the mist chamber.

The medicament delivery system further includes a cup-shaped medicamentampoule having a removable (for example, by peeling off a foil cover)seal adapted to fit within the mist chamber-defining element. Theampoule has an open-faced interior region defined by a base member. Theinterior region extends from an open top ring at a top end along anampoule axis to a closed end opposite the top end, wherein the closedend has an outer surface complementary to the energy delivery surface ofthe ultrasonic transmission horn. The ampoule is adapted to fit withinthe mist chamber-defining element with the outer surface of the closedend of the ampoule fitting in intimate contact with the energy deliverysurface of the ultrasonic transmission horn. The ampoule furtherincludes a medicament disposed in the interior region of the ampoule andwherein the open top ring of the ampoule is spanned by a sheet memberwhereby the interior region of the ampoule is closed.

The sealed unit dose ampoule (filled with the relevant medicament) ispositionable into the device (with its seal intact), and when the sealis removed, the ampoule acts as both a dose cup negating the need for aseparate baffle. With that configuration, drug handling is limited, thelikelihood of spillage of the medicament is reduced, and consequently aconsistent dose can be delivered. In a preferred form, the ampoule isdisposable, minimizing the number of components to be cleaned.

The ampoule of the present invention is preferably essentially a small,thin walled cup. In one preferred embodiment, the unit dose ampouleincludes an upper screw thread portion, a location ring and a conicalbase. The upper screw thread portion is adapted to be screw connectedwith the open-faced end of the mist chamber-defining element. Thelocation ring allows the ampoule to be positioned within the nebulizerdevice. The base is preferably conical shaped to allow the ultrasonicenergy conducted from the ultrasonic system to be concentrated at thebase of the ampoule. This design also enables fluid returning ofactivated medicament from the sides of the ampoule to the point at whichall the ultrasonic energy is concentrated. The ampoule has apredetermined volume designed to contain a required dose of medicament.

The inhalation port includes an inhalation valve, a main chamber and anexhalation valve. During inhalation by a user, the inhalation valveopens to allow passage of aerosol mist into the main chamber of theinhalation port and subsequently into the patient. At the same time theexhalation valve remains closed. During exhalation, the exhalation valvebecomes operational to allow the breath to pass out of the inhalationport without entering the mist chamber, at the same time the inhalationvalve remains closed to prevent breathing back into the dose unit.

The present invention is applicable for both solutions and suspensions.Drug applications may include all nebulized formulations, particularlyin the following therapeutic areas—Asthma, COPD, Cystic Fibrosis,infections of any type responsive to antibiotic treatment, and paintreatment of any type.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a nebulizer assemblyin accordance with the invention.

FIG. 2 is a perspective view of the nebulizer assembly of FIG. 1partially cut-away to reveal internal components thereof.

FIGS. 3A and 3B are perspective views of one embodiment of the mistchamber-defining element of the nebulizer assembly of FIG. 1.

FIG. 4 is a perspective view of one embodiment of a unit dose ampoulefor use with the nebulizer of FIG. 1, having a frangible seal.

FIG. 4A is a perspective view of one embodiment of a unit dose ampoulefor use with the nebulizer assembly of FIG. 1.

FIG. 4B is a bottom view of the unit dose ampoule of FIG. 4A.

FIG. 5 is a perspective view of the nebulizer housing for the nebulizerassembly of FIG. 1.

FIG. 5A is an exploded side view of the nebulizer assembly of FIG. 1.

FIG. 6 is a perspective view of the inhalation port of the nebulizerassembly of FIG. 1.

FIG. 6A illustrates one embodiment of the valve and retainer disc foruse in the inhalation port of the nebulizer assembly of FIG. 1.

FIG. 6B illustrates another embodiment of the valve and retainer discfor use in the inhalation port of the nebulizer assembly of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

For a better understanding of the invention, the following detaileddescription refers to the accompanying drawings, wherein preferredexemplary embodiments of the present invention are illustrated anddescribed. In addition, the reference numbers used to identify likeelements in the drawings are the same throughout.

The present invention, a medicament delivery system, comprises anebulizer device, an open-faced mist chamber-defining element having atubular input/output port, coupling means for selectively coupling thecoupling end of the mist chamber-defining element to the energy deliveryend of the nebulizer device, a tubular inhalation port extending betweena user end and a device end, a bidirectional valve assembly, and asealed unit dose ampoule adapted to fit within the mist chamber-definingelement. The nebulizer device includes an ultrasonic transducerresponsive to applied electrical energy to generate ultrasonic energy,an ultrasonic transmission horn between an input energy surface at aninput end and an energy delivery surface at an output end. The sealedunit dose ampoule can be placed directly into the nebulizer device andacts as both the dose cup and baffle, so that the chance of spillage ofdrug and the number of components to be cleaned are minimized. The unitdose ampoule has a conical base to allow ultrasonic energy conductedfrom the ultrasonic system to be concentrated at the base of theampoule. The inhalation port includes an inhalation valve and anexhalation valve.

FIG. 1 and FIG. 2 illustrate an exemplary nebulizer assembly 10embodying the present invention. As shown in FIGS. 1 and 2, thenebulizer 10 comprises a nebulizer 11, a mist chamber-defining element12, an ampoule 14 for receiving medicament attached to the mistchamber-defining element 12, and a housing 16 enclosing an electricallydriven ultrasonic system for generating ultrasonic energy and couplingthat ultrasonic energy to the ampoule 14. The generally dome shaped mistchamber-defining element 12 together with the ampoule 14 defines asubstantially closed mist chamber above the ampoule 14.

FIG. 2 is a perspective view of the nebulizer assembly of FIG. 1partially cut-away to reveal internal components thereof. The nebulizer11 includes a housing 16 extending along a housing axis A from a baseend 13 to an energy delivery end 19. The housing 16 includes anultrasonic transducer 21 responsive to applied electrical energy togenerate ultrasonic energy at an output surface 17, and an ultrasonictransmission horn 23 extending along the housing axis A between an inputenergy surface 25 at an input end and an energy delivery surface 27 atan output end. The input energy surface 25 is acoustically coupled tothe output surface 17 of the transducer. The horn 23 is adapted totransmit ultrasonic energy applied at the input energy surface 25 alongthe housing axis A to the energy delivery surface 27. The open-facedmist chamber-defining element 12 extending along a chamber axis C fromthe coupling end 29. The mist chamber-defining element 12 includes atubular input/output port 31 extending along a port axis B, and the portaxis B is angularly offset from the chamber axis C. The interior volumeof the mist chamber-defining element 12 is opposite the energy deliverysurface 27 of the horn 23 and the chamber axis C is substantiallyparallel to the housing axis A. Preferably, the chamber-defining element12 is dome-shaped, so that when its open face is coupled to a perimeterof the ampoule 14, it defines the substantially closed mist chamber.

FIGS. 3A and 3B show a chamber-defining element of one preferredembodiment of the present invention. The chamber-defining element 12includes a domed main chamber wall 18, an inhalation tube 20 incommunication with the interior mist chamber defined by chamber wall 18,and a lower screw thread portion 22 extending from the main chamber wall18 to the coupling end 29 of the chamber-defining element 12. Thechamber wall 18 has vertical walls and a domed roof, the highest pointof which being located at the center of the chamber cross-section andbeing, but not limited to, a hemispherical shape. The roof and chamberdefined by chamber wall 18 are preferably smooth to allow condensed mistto run back down to be nebulized again to ensure efficient delivery of ahigh percentage of the dose. Other geometries of mist chamber may beused to create the same effect.

The inhalation port assembly formed by inhalation tube 20 is made up oftwo concentric tubes 20A and 20B. In the illustrated embodiment, thecross-sectional areas of the inner and outer tubes are the same toequilibrate the flow of air into and out of the chamber. Othergeometries may be used in different forms of the invention. Theinhalation tube 20 preferably connects to the wall 18 near the bottom ofthe mist chamber-defining element to avoid drawing in of medicament witha liquid form.

As shown in FIG. 4, FIG. 4A and FIG. 4B, the ampoule 14 has anopen-faced interior region defined by a base member 35. The interiorregion is extending from an open top ring 31 at a top end 33 along anampoule axis D to a closed end 37 opposite the top end 33, wherein theclosed end 37 has an outer surface 39 complementary to the energydelivery surface 27 of the ultrasonic transmission horn 23. The ampoule14 is adapted to fit within the mist chamber-defining element 12 withthe outer surface 39 of the closed end 37 of the ampoule 14 fitting inintimate contact with the energy delivery surface 27 of the ultrasonictransmission horn 23.

As shown in FIG. 4, The ampoule 14 may further include a medicamentdisposed in the interior region of the ampoule and wherein the open topring 31 of the ampoule is spanned by a sheet member 32 whereby theinterior region of the ampoule is closed. The frangible sealed sheetmember 32 across the top may be removed by tearing, piercing orbreaking. In a preferred embodiment, the frangible seal member 32 is afoil or plastic lid, which is sealed to the ampoule 14 by ultrasonicweld or glue. The foil membrane has a side tab 34, or centralizedsemi-circular attachment to aid removal of the seal. The lid 32 ispreferably not removed until the ampoule 14 is locked into thenebulizer. This design prevents spillage of the medication and reducespatient handling of the ampoule and the medicament. The lid 32 ispreferably made from materials with low heat conductivity, low surfacetension (to prevent coagulation of particles), and ease of manufacture.

As shown in FIG. 4A, the ampoule 14 of the present invention isessentially a small, thin walled cup having a conical base, to allow theultrasonic energy conducted from the ultrasonic system to beconcentrated at the base of the ampoule. In one preferred embodiment,the unit dose ampoule 14 includes an upper screw thread portion 24, alocation ring 26, and a conical base 28. The screw thread of the upperscrew thread portion 24 has equal pitch and length to the screw threadof the lower screw thread portion 22 of the chamber-defining element 12to allow attachment of the ampoule 14 to the mist chamber-definingelement 12 to form a complete unit. The fixture between mistchamber-defining element 12 and ampoule 14 is not limited to a screwthread. A snap/push fit or interference fit may be employed. The base 28is preferably conical shaped to allow the ultrasonic energy toconcentrate at the base of the ampoule. The conical shaped base alsoenables nebulized or activated medicament to run down the sides of theampoule 14 to a bottom point at which all the ultrasonic energy isconcentrated. The location ring 26 allows the ampoule 14 to be receivedand positioned at the top of the housing 16. The ring is preferablycircular, but circumstances may require a triangular, rectangular, hexor pentagonal design adapted for using with different designed housingsor ultrasonic systems. As best shown in FIG. 4B, two tabs 30 extend fromthe location ring 26. These tabs act to lock the ampoule 14 in thehousing 16. The tabs are preferably spaced at an angle not equal to 180degrees to ensure that the ampoule may only be oriented in onedirection. In one preferred embodiment, an angle of 120 degrees has beenchosen. The number of side tabs may not be limited to two. Also othermeans for coupling the chamber-defining element, the ampoule and thehousing (and its ultrasonic generator) may be used.

In a preferred embodiment, as shown in FIG. 5 and FIG. 5A, the housing16 of the present invention includes a main casing 36, a threaded collar38, a cover 40, and a base 42. The top of the main casing 36 includes athreaded cylindrical section 44 with two cutout sections 46 toaccommodate the two tabs 30 of the ampoule 14. The threaded collar 38 isscrew mounted onto the threaded cylindrical section 44 of the maincasing 36. The cover 40 is rotatably mounted onto the threaded collar38, preferably snap-fitted to the collar 38. In one preferred embodiment(not shown in the figures), the cover 40 has two angularly offset stopplates engaged with one stop plate of the housing 16, thus only limitedmovement of the cover relative to the housing is permitted. The cover 40further includes two cutouts 48, which are adapted to receive the twotabs 30 of the ampoule 14. When the cover 40 is rotated to a firstposition, the two cutouts 48 are aligned with the two cutout sections 46of the housing 16, and the ampoule may be placed into a conical recessof the housing 16 with the two tabs 30 fitting into the two cutouts 48of the cover 40 and the two cutout sections 46 of the housing 16. Whenthe cover is rotated to a second position, the ampoule tabs are retainedin the two cutout sections 46 of the housing 16, and the ampoule 14 islocked into the housing 16. In operation, after the ampoule 14 is placedand locked in the housing 16 and the lid 32 is removed, the mistchamber-defining element 12 is then screwed onto the top of the ampoule.The screw thread of the mist chamber-defining element is preferablydesigned to begin in one place to ensure that the inhalation tube on themist chamber-defining element is oriented towards the front of thenebulizer body.

The nebulizer of the present invention further comprises an ultrasonictransducer disposed within the housing 16. The ultrasonic transducer isselectively responsive to applied electrical energy to generateultrasonic energy, which is coupled via a transmission horn from anoutput surface of the transducer to an energy delivery surface near thetop of the housing 16. The energy delivery surface is adapted to be inintimate contact with the conical base 28 of the ampoule 14, so thatsaid energy transfer occurs. The delivered energy causes nebulization ofthe medicament.

Thus, the ultrasonic energy passes from the ultrasonic transducer,through the conical base of the unit dose ampoule 14 and into theaqueous medicament. This energy creates a fountain of liquid inside theampoule and the mist chamber, and enables molecules with enough energyto break away from the fountain, creating the aerosol mist. This mistthen is inhaled by a patient to the lungs of the patient.

As shown in FIG. 6, the inhalation port 15 extends between a user end 61and a device end 63. Inhalation port 15 includes a bidirectional valveassembly made of two unidirectional valves. One valve is an inhalationvalve 62, and the other one is an exhalation valve 64. Duringinhalation, the inhalation valve 62 opens to allow passage of theaerosol mist into a main chamber 66 of the inhalation port 15 andsubsequently into the patient's lungs. At the same time the exhalationvalve 64 remains closed. The exhalation valve 64 positioned in the sidetube section becomes operational during exhalation to allow the breathto pass out of the inhalation port without entering the mist chamber, atthe same time the inhalation valve 62 remains closed to preventbreathing back into the mist chamber.

The preferred embodiments of the inhalation and exhalation valves eachincludes a small, thin, rubber disc element 69A that is mounted to coverradial holes in a frame element 69B that allows the passage of air. InFIG. 6A, part A shows an exploded view of the valve, and parts B and Cshow front and rear views respectively. The disc element 69A includes astem 70 in the center and a four segment thin rubber disc 72. Duringinhalation or exhalation, the peripheral portions of the thin rubberdisc lift away from the frame element 69B, allowing the inhaled mist topass into the inhalation port, or the exhaled breath into the air.

FIG. 6B shows another preferred embodiment of the valves. As shown inFIG. 6B, the valve has a valve housing 74 and a thin semicircular discsegment 76 with a pair of pins 78 extending therefrom. The disc segment76 is pivotally connected to the valve housing 74 by the pins 78 and aretaining ring 79. A spring 80 biases the disc 76 toward a closedposition. During inhalation or exhalation, the disc segment 76 liftsaway from the housing 74, allowing the inhaled mist to pass into theinhalation port, or the exhaled breath into the air. During the oppositeportion of the breathing cycle, the spring 80 forces the valve to beclosed.

The bidirectional valve assembly, and the inhalation port 15 generally,define a unidirectional airflow path only from the interior volume ofthe mist chamber to the user end 61 of the inhalation port 15 when thepneumatic pressure in the inhalation port 15 is lower than the pneumaticpressure in the interior volume of the mist chamber. The valve assembly60 also defines a unidirectional airflow path only from the user end ofthe inhalation port to the exterior points when the pneumatic pressurein the inhalation port is greater than the pneumatic pressure in theinterior volume of the mist chamber.

The discs in both embodiments of FIG. 6A and FIG. 6B may only be liftedin one direction, so that the valves are remained close when the airbreath comes from an opposite direction.

There are no restrictions on dimensions with the exception that theinternal dimensions allow insertion of the inhalation and exhalationvalves, and the inhalation port can be attached to the inhalation tubeof the mist chamber-defining element.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range of theequivalency of the claims are therefore intended to be embraced therein.

1. A medicament delivery system comprising: A. a nebulizer including ahousing extending along a housing axis from a base end to an energydelivery end, said housing including therein: i. an ultrasonictransducer responsive to applied electrical energy to generateultrasonic energy at an output surface thereof; ii. an ultrasonictransmission horn extending along said housing axis between an inputenergy surface at an input end and an energy delivery surface at anoutput end, said input energy surface being acoustically coupled to saidoutput surface of said transducer, said horn being adapted to transmitultrasonic energy applied at said input energy surface along saidhousing axis to said energy delivery surface, B. an open-faced mistchamber-defining element extending along a chamber axis from anopen-faced coupling end and said mist chamber-defining element includinga tubular input/output port extending therefrom along a port axis, saidport axis being angularly offset from said chamber axis, C. couplingmeans for selectively coupling said open-faced coupling end of said mistchamber-defining element to said energy delivery end of said housingwhereby said interior volume of said mist chamber-defining element isopposite said energy delivery surface of said horn and said chamber axisis substantially parallel to said housing axis, D. a tubular inhalationport extending between a user end and a device end, E. a bidirectionalvalve assembly having a first port coupled to said device end of saidinhalation port, a second port coupled to said port of said mistchamber-defining element and a third port coupled to points exterior tosaid bidirectional valve assembly, wherein said valve assembly defines aunidirectional airflow path only from said interior volume of said mistchamber-defining element to said user end of said inhalation port whenthe pneumatic pressure in said inhalation port is lower than thepneumatic pressure in said interior volume of said mist chamber-definingelement, and wherein said valve assembly defines a unidirectionalairflow path only from said user end of said inhalation port to saidexterior points, when the pneumatic pressure in said inhalation port isgreater than the pneumatic pressure in said interior volume of said mistchamber-defining element.
 2. A medicament delivery system according toclaim 1, further comprising: a cup-shaped medicament ampoule having anopen-faced interior region defined by a base member extending from anopen top ring at a top end along an ampoule axis to a closed endopposite said top end, wherein said closed end has an outer surfacecomplimentary to said energy delivery surface of said ultrasonictransmission horn, and wherein said ampoule is adapted to fit withinsaid mist chamber-defining element with said outer surface of saidclosed end of said ampoule fitting in intimate contact with said energydelivery surface of said ultrasonic transmission horn.
 3. A medicamentdelivery system according to claim 1 wherein said ampoule includes amedicament disposed in said interior region of said ampoule and whereinsaid open top ring of said ampoule is spanned by a sheet member wherebysaid interior region of said ampoule is closed.
 4. A medicament deliverysystem according to claim 3 wherein said sheet member is removable.
 5. Amedicament delivery system according to claim 3 wherein said sheetmember is frangible.
 6. A medicament delivery system according to claim1 wherein aid mist chamber-defining element is dome-shaped.
 7. Amedicament delivery system according to claim 1 wherein said port axisis offset from said chamber axis by an angle in the range 35 to 55degrees.
 8. A medicament delivery system according to claim 1 whereinsaid port axis is offset from said chamber axis by 45 degrees.
 9. Amedicament delivery system according to claim 1 wherein said energydelivery surface is cone-shaped.
 10. A medicament delivery systemaccording to claim 1 wherein said bi-directional valve assembly is adiscrete assembly adapted for removable coupling of said second port ofsaid bi-direction valve assembly.
 11. A medicament delivery systemaccording to claim 1 wherein said bi-directional valve assembly isintegral with said port of said mist chamber-defining element.
 12. Amedicament delivery system according to claim 1 wherein said mistchamber-defining element is transparent.
 13. A medicament deliverysystem according to claim 1 wherein said mist chamber-defining elementis translucent.
 14. A medicament delivery system according to claim 1wherein said mist chamber-defining element is opaque.